This is not a virus but a Windows-based trojan horse.
Once detected, the F-Secure security product will automatically disinfect the suspect file by either deleting it or renaming it.
There are two variants of the backdoor. They have been circulated in e-mail and newsgroups postings as attachment files called PICTURE.EXE and MANAGER.EXE, sized 353792 bytes and 348672 bytes. Both of them copy themselves to the Windows directory as a file called NOTE.EXE file name and register themselves to be executed every time Windows boots up.
After this, the trojan gathers information from the machine, including username and password, copies them to an encrypted DAT file and tries to e-mail that file to addresses email@example.com and firstname.lastname@example.org.
This trojan does not spread by itself. It can be removed simply by deleting the NOTE.EXE file and the original carrier file. It is recommended that you change your password if you believe to be affected by this trojan.
Backnote was widespread between Christmas and New Year 1998.
Technical Details: Mikko Hypponen, F-Secure